/*
 * Copyright 1999-2011 Alibaba Group.
 *  
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alibaba.dubbo.container.page;

import java.io.Serializable;
import java.util.Comparator;

/**
 * MenuComparator
 * 
 * @author william.liangf
 */
public class MenuComparator implements Comparator<PageHandler>, Serializable {

    private static final long serialVersionUID = -3161526932904414029L;

    public int compare(PageHandler o1, PageHandler o2) {
        if (o1 == null && o2 == null) {
            return 0;
        }
        if (o1 == null) {
            return -1;
        }
        if (o2 == null) {
            return 1;
        }
        return o1.equals(o2) ? 0 : (o1.getClass().getAnnotation(Menu.class).order() 
                > o2.getClass().getAnnotation(Menu.class).order() ? 1 : -1);
    }

}